Generation of Multichannel Coaxial Quasiperfect Vortex Electromagnetic Waves With Equal Divergence Radii Based on Aperture-Shared Metasurface

Abstract

Vortex electromagnetic (EM) waves hold significant promise for next-generation wireless communication applications. However, their practical deployment is hindered by varying divergence characteristics across vortex modes with different mode numbers. To overcome this challenge and enable true spatial multiplexing of orbital angular momentum (OAM) waves, a dual-polarized shared-aperture metasurface is proposed. By leveraging both polarization and OAM multiplexing, quasiperfect vortex (QPV) EM waves with coaxial beams and equal divergence radii are successfully generated at microwave frequencies. Initially, the properties of QPV waves in the microwave band are analyzed, followed by the design of a dual-polarized metasurface unit. This unit integrates parasitic damping-coupled patches based on the traditional Jerusalem cross structure, providing polarization-independent control and approximately 360° phase-tuning capability. Furthermore, simulations validate the effectiveness of the dual-polarized single-mode metasurface design. Based on this, the concept is extended to a 4-channel multiplexing metasurface, operating at 15 GHz and capable of generating QPV waves. Finally, experimental results from the fabricated metasurface demonstrate the generation of QPV waves with OAM mode numbers 0, +2, +1, and −1, achieving simulated and measured OAM mode purities of 0.835 and 0.70, respectively. The experimental data closely aligns with simulations, confirming the effectiveness of the design. This study offers new insight into generating and applying perfect vortex EM waves, paving the way for high-capacity near-field wireless communication systems and advanced control of novel EM physical dimensions.